Goblint server `files` request does not include names of analyzed files when `pre.enabled = false`

[karoliineh]

While using the abstract debugger on an analysis that used svcomp24 configuration, adding a breakpoint to a program point that had a warning showed a greyed-out breakpoint with the message "file not analyzed". Looking into it revealed that when in the configuration pre.enabled is set to false, the server does not return the actual file name that was analyzed with the files request, which results in GobPie not being able to set the requested breakpoint.